1. Field of the Invention
This invention relates to a method and apparatus for reducing the liquid content of a layer of material formed on a filter.
2. Prior Art
Frequently, filter cakes, that is, a layer of material formed on a filter during filtration, more particularly layers of solid particles formed by extraction of a liquid from a suspension of the solid particles in the liquid, have to be further dried because the residual liquid content is excessive. For example, when certain products, more particularly dyes, are filtered on continuously operating vacuum filters, the filter cakes have an undesirably high residual moisture content (approx. 70 - 85%). This is due mainly to cracks forming during suction-drying and resulting in non-uniform suction.
In the prior art, the filter cake is subsequently mechanically dried in special devices remote from the filter press. This results in relatively high capital expense and a large amount of space is required.